1. Field of the Invention
The present invention generally relates to a locking cap and key combination for open ends of plumbing components and, more specifically, to a protective locking cap and key combination for threaded openings in couplings, fixtures and the like. Even more specifically, the present invention relates to a locking cap and key combination for fire retardant sprinkler systems utilizing charging pipes.
2. Description of the Related Art
In fire protection systems that include automatic sprinkler systems having multiple sprinkler heads, the standing water supply is often not sufficient to maintain optimum operating water pressure when there are several sprinkler heads in simultaneous operation. Accordingly, the National Fire Protection Association Code requires a connection through which a fire department can pump water into the sprinkler system in order to charge or recharge the sprinkler system. Where such connections are provided, upon arrival of fire department personnel, an auxiliary source of water supply, usually a hose supplied with water from a fire truck pump, may be connected to a union connection advantageously located outside the building. Such hose connections are often termed siamese connections and are fitted with union nuts having an internal thread sized and configured to match the external thread of the hose of the local fire department. Also, in most instances, the union nut is loosely retained on the inlet pipe through a bearing arrangement and is provided with radially extending parts adapted to be operated by a “spanner” wrench carried by most firefighters.
The National Fire Protection Association Code also specifies that such hose connections shall be equipped with plugs or caps. Because the hose connections are in public locations which may be unsecured, the plugs or caps are desired to reduce the likelihood that passersby, vandals, or arsonists will damage the connections and render the connections inoperable. Thus, the plugs or caps cover the auxiliary water inlet to the sprinkler system to prevent malicious introduction of trash or other debris. Such trash and debris might clog the sprinkler system when it is needed most.
Several types of caps or plugs have heretofore been provided to cover the union nut of siamese connections and protect the integrity and operability of the sprinkler system. One such arrangement includes an easily breakable cap, made of cast iron for example, which cap is attached to the union nut by U-bolts carried by the cap but adapted to engage the posts of the union nut to hold the cap in place. Such cap members have been particularly vulnerable to vandalism and are particularly susceptible to breakage at the points where the U-bolts are received in the cap. Furthermore, even where the cap is not broken, certain portions of the cap rust through over time and the caps simply fall off. In addition, because of the differences in coefficients of thermal expansion between the union nut and the cap, the cap is also susceptible to breakage.
Another common device is a brass plug having external threads to be received in the union nut where the plug, like the union nut, is provided with radially extending posts to be operated by a spanner wrench. The union nut of such siamese connections is usually brass so it is necessary to provide brass plugs, which are of substantial scrap value. Accordingly, because of their location in often unsecured public places, the plugs are frequently stolen for resale as scrap.
Summary of the Invention
Accordingly, a locking cap is desired for a standpipe that can be securely mounted so that it is not easily removed by unauthorized personnel. Additionally, such a locking cap desirably is quickly removed by authorized personnel under time pressures and mental anxiety. Moreover, such a locking cap should be relatively impervious to climatic elements such that deterioration over time is reduced.
Thus, the present invention provides a locking cap and key combination that is virtually tamperproof such that it cannot be removed without substantial destruction thereof, but which is not susceptible to inadvertent breakage. Moreover, the locking cap is easily removed at the appropriate time by authorized personnel utilizing a specially designed mating key arrangement. Furthermore, another aspect of the present invention provides a straightforward cap design which is easily and economically fabricated, and which is easily attached to secure a fire sprinkler system.
One feature of the present invention is the universal nature of the key and locking cap. While it is advantageous to prevent vandals and the like from removing the locking cap, the locking caps are configured with a unique locking mechanism which allows the fire department, or other authorized personnel, to use a single key to unlock every locking cap within their jurisdiction. This capability may prove important during crisis situations requiring rapid response. Specifically, the use of a single key eliminates the need to rifle through a variety of keys to find the proper key to remove the subject locking cap. Additionally, the locking caps may be serialized to empower a fire department or other entity with an ability track their location in the event of a lost, stolen or otherwise transferred locking cap.
One aspect of the present invention involves a locking cap for a pipe end. The locking cap has a faceplate and a plug portion. The faceplate has a front surface and a rear surface while the plug portion has a front surface, a rear surface and a side surface. A slot extends longitudinally between the front surface and the rear surface and radially between the side surface and a relief opening. Additionally, a channel is defined along the slot proximate the side surface. The plug portion is connected to the faceplate with the rear surface of the faceplate arranged to substantially face the front surface of the plug portion. Moreover, the plug portion is sized and configured to be received by the pipe end. The channel receives a translatable spreader member wherein at least one surface of the spreader member or the channel is tapered such that the spreader member and the channel cooperate to expand and retract the plug portion.
Another aspect of the present invention involves a locking cap for a tubular opening. The locking cap generally comprises a cap body having an expansion member and a spreader member. The expansion member and the spreader member include a sloping engagement face such that relative axial movement of the expansion member and the spreader member results in radial displacement of at least a portion of the expansion member. The radial displacement of the portion of the expansion member urges the expansion member into a frictional interlock with an inner surface of the opening.
Yet another aspect of the present invention involves a locking cap for a pipe end generally comprising a faceplate. The faceplate includes a front surface and at least two pins projecting from the front surface. The faceplate also has a back surface and is connected to a plug portion such that the back surface of the faceplate is proximate a surface of the plug portion. At least a portion of the plug portion is capable of selective expansion and contraction to create a frictional interlock between the locking cap and the pipe end.
Another aspect of the present invention involves a lockable closure for an open end of a tubular element. The closure generally comprises a radially expanding member and an actuator shaft. The actuator shaft has a first end and a second end with the first end of the actuator shaft having a keyed configuration. The second end of the shaft extends through the closure into the tubular element. The actuator shaft is rotatable relative to the closure and is connected to the radially expanding member such that rotation of the actuator shaft in one direction effects generally outward movement of the radially expanding member and rotation of the actuator shaft in the other direction effects generally inward movement of the radially expanding member.